1. 2.2 Periodic Table Origin of the periodic table
Chemists in the 10th century wished to organize elements
Attempts focused on grouping elements with similar properties
In 1867, Dimitri Mendeleev found patterns in the elements and organized them into table
The resulting table had holes for elements
not yet discovered

2. Periodic Table The Periodic Table provides information
on the physical and chemical properties of elements
Atomic Mass - mass of average atom
Atomic Number - number of protons
Ion Charge - electric charge that forms when an atom gains or loses electrons

3. Periodic Table

4. Metals, Non-metals, Metalloids
Period table has interesting patterns
Due to Mendeleev’s organization, interesting patterns are created, such as the groups: metals, non-metals and metalloids.

5. Periods and Families
Each horizontal row in the periodic table is a period
Vertical columns form groups or chemical families
Alkali metals - highly reactive group 1
Alkaline earth metals - group 2, burn in air if heated
Halogens - group 17, highly reactive non-metals
Noble gases - group 18, stable and unreactive non-metals
Take the Section 2.2 Quiz